摘要
目的:针对结直肠癌(CRC)患者探究能谱CT个体化低剂量成像方案的可行性及其对图像质量的影响。方法:常规组(A组)回顾性收集行能谱CT全腹增强检查的CRC患者147例。实验组(B组)前瞻性收集行能谱CT全腹增强检查的CRC患者146例。A组管电压80/140kV瞬切,管电流固定400mA;B组管电压80/140kV瞬切,管电流采用GSI-Assist模式,噪声指数(NI)设为12。A组重建70keV结合后置40%自适应统计迭代算法(ASIR-V)动、静脉期图像,B组重建70keV结合后置40%~80%ASIR-V(间隔10%)的动、静脉期图像,记为B1~B5组。计算两组的有效辐射剂量(ED)。在轴位图像上测量肠系膜上动脉(SMA)主干、肠系膜下动脉同层腹主动脉(AA)、肠系膜上静脉(SMV)以及CRC的CT值和SD值,并计算上述目标的信噪比(SNR)、对比度噪声比(CNR)。由2名放射科医师采用盲法对图像质量和病灶显示进行五分制评价,采用Kappa检验比较主观评分一致性。结果:B组ED相较于A组降低34.51%(P<0.05)。B3组SMA、AA、SMV和CRC的SNR和CNR与A组相当(P>0.05)。2名医师主观评分一致性良好(Kappa值:0.806~0.915;P<0.05)。B组内动、静脉期整体图像质量评分和病灶显示情况均为B3组得分最高,且与A组相当(均P>0.05)。结论:基于GSI-Assist技术和高NI并联合后置60%ASIR-V的成像参数能够实现CRC患者的个体化能谱低剂量成像。该方案可在辐射剂量降低约35%的情况下,保证结直肠癌能谱CT增强检查的图像质量。
Purpose:To investigate the feasibility of an individualized low-dose spectral CT imaging protocol for patients with colorectal cancer(CRC)and to evaluate its impact on image quality.Methods:A total of 147 CRC patients who underwent contrast-enhanced abdominal spectral CT scans with a standard protocol were retrospectively enrolled as the control group(Group A).Another 146 CRC patients who underwent similar scans with a prospective,individualized low-dose protocol were included as the experimental group(Group B).Group A utilized fixed tube current(400 mA)with fast tube voltage switching between 80 and 140 kV.Group B employed the GSIAssist mode[noise index(NI)=12]for automatic tube current modulation with the same tube voltage switching.For reconstruction,Group A images(arterial and venous phases)were generated at 70 keV combined with 40%adaptive statistical iterative reconstruction-Veo(ASIR-V).For Group B,five image sets(B1-B5)per phase were reconstructed at 70 keV with increasing ASIR-V levels from 40%to 80%(in 10%increments).The effective radiation dose(ED)was calculated for both groups.On axial images,the CT value and its standard deviation(SD)were measured in the superior mesenteric artery(SMA),abdominal aorta(AA)at the level of the inferior mesenteric artery,superior mesenteric vein(SMV),and the CRC lesion.The signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)for these regions were subsequently calculated.Two radiologists,blinded to the scanning and reconstruction parameters,independently scored the overall image quality and lesion clarity using a five-point scale.Interobserver agreement was assessed using the Kappa test.Results:The ED for Group B decreased by 34.51%compared with Group A(P<0.05).The SNR and CNR values for the SMA,AA,SMV and CRC in Group B3 were comparable to those in Group A(P>0.05).Interobserver agreement for subjective image assessment was excellent(Kappa value:0.806-0.915;P<0.05).Within Group B,images from subset B3 received the highest scores for overall image quality and lesion clarity in both arterial and venous phases,and these scores were not significantly different from those of Group A(all P>0.05).Conclusion:An individualized low-dose spectral CT imaging protocol for CRC patients,utilizing GSI-Assist with a high Ncombined with 60%ASIR-V reconstruction,is feasible.This protocol can reduce radiation dose by approximately 35%while maintaining image quality comparable to that of a standard-dose protocol in contrastenhanced spectral CT for CRC.
作者
张竞颐
魏强
刘义军
王诗耕
杜长谕
何健
ZHANG Jingyi;WEI Qiang;LIU Yijun;WANG Shigeng;DU Changyu;HE Jian(Department of Radiology.The First Affiliated Hospital of Dalian Medical University)
出处
《中国医学计算机成像杂志》
北大核心
2026年第1期80-88,共9页
Chinese Computed Medical Imaging
